Creating Boundary Condition for ROMS Grid using GODAS Data

[prasannakanti]

While running the script for creating boundary condition I got the following error:

Traceback (most recent call last): File "/home/prasanna/miniconda/envs/xesmf_env/lib/python3.7/multiprocessing/pool.py", line 121, in worker result = (True, func(*args, *kwds)) File "/home/prasanna/miniconda/envs/xesmf_env/lib/python3.7/multiprocessing/pool.py", line 44, in mapstar return list(map(args)) File "withcomment_Boundary_condition_genertion_from_Godas_to_ROMS.py", line 65, in do_file zeta = remap_bdry(file, 'SSH', src_grd, dst_grd, dst_dir=dst_dir) File "/home/prasanna/MOM6/GodasToROMS_BC/remap_bdry.py", line 43, in remap_bdry src_var = cdf.variables[src_varname] KeyError: 'SSH'

I am unable to find the exact problem. Can you please help me in this issue?

[kshedstrom]

Is the variable "SSH" in the GODAS file?

[prasannakanti]

Yes. There are ssh,salt,temp variables.

[kshedstrom]

If the file has ssh, you should change the code to ssh from SSH.

[prasannakanti]

Sorry madam. It was 'SSH' in the Godas file. I kept the same name as it is in Godas data.

[kshedstrom]

Then I can't tell what the problem is. Is there a version of the script you can try without the multiprocessing? That might give more informative errors. Have you learned to use the pdb debugger?

[prasannakanti]

No madam. I do not know how to use pdb debugger. I am checking the script again.Thank you.

[prasannakanti]

This is my Godas dataset . 1> ./Godas_uvsshts_Jan.nc (default) name title I J K L U zonal current 1:720 1:410 1:40 1:31 V meridional current 1:720 1:410 1:40 1:31 SSH sea surface height 1:720 1:410 ... 1:31 TEMP Potential temperature 1:720 1:410 1:40 1:31 SALT Salinity 1:720 1:410 1:40 1:31 ETA_T surface height on T cells 1:720 1:410 ... 1:31 WT vertical velocity T-points 1:720 1:410 1:40 1:31 MLD mixed layer depth 1:720 1:410 ... 1:31 AVERAGE_DT Length of average period ... ... ... 1:31

[prasannakanti]

Madam, This ** line is the line where the error coming . src_varname is then defined below under if, elif condition.

cdf = netCDF.Dataset(src_file)

src_var = cdf.variables[src_varname]

time = cdf.variables['time'][0]
print(time)

#get missing value
spval = src_var._FillValue
src_var = cdf.variables[src_varname][0]

# determine variable dimension
ndim = len(src_var.shape)

if src_varname == 'SSH':
    pos = 't'
    Cpos = 'rho'
    z = src_grd.z_t
    Mp, Lp = dst_grd.hgrid.mask_rho.shape
    dst_varname = 'zeta'
    dimensions = ('ocean_time', 'eta_rho', 'xi_rho')
    long_name = 'free-surface'
    dst_varname_north = 'zeta_north'
    dimensions_north = ('ocean_time', 'xi_rho')
    long_name_north = 'free-surface north boundary condition'
    field_north = 'zeta_north, scalar, series'
    dst_varname_south = 'zeta_south'

[prasannakanti]

@kshedstrom Madam, your help is required . Please help me a bit.

[prasannakanti]

@kshedstrom Hope you are doing well. I created the boundary files. But I could not open then in Ferret. It is showing the following error. us Godas_day_27_bdry_GODASROMSBC.nc NOTE: NOTE: Could not adjust grid for variable h **ERROR: inconsistent data grids: File needs axis attributes on coordinate variables indicating correct directions Kindly help me a little. But I can plot and check in python . Please help me .

[kshedstrom]

You're asking me for help with ferret? Really? If it wants more attributes, you can add them via Python or via the NCO package. ncatted -a ... The real question is does ROMS happily read them?

[prasannakanti]

Yes madam, I was so much disapointed when I could not open the .nc file in ferret. I thought you can help me. Python can read the files. I did not start any model run. Thank you.

[kshedstrom]

I have not used ferret. Before Python I was doing a few things in NCL and before that I was playing with PDL (Perl Data Language). Both are now completely obsolete thanks to Python and xarray and all that. To view netcdf files I have been using ncview all along. Also "ncdump -h".

[prasannakanti]

Thank you Madam for your time. I am new in python and using .nc file. I have checked and found it was a problem with the ferret version. It is opening in other ferret versions. Thank you again.

[prasannakanti]

Madam, I am facing another problem. I have used Data variables' _fill_value in the destination variables. But, when the destination variables coming, it is showing distinct fill_values. Even fill plot for temp and salt are coming odd without levels qualifier.

[kshedstrom]

Did you start from one of my examples? Which one? I don't have a Godas example.

[prasannakanti]

Yes madam. I started with your "CCS1_SODA3.3.1" example. I used almost the same code but the data source I used from GODAS.

[kshedstrom]

The code should copy the source _FillValue to the destination variables. On the command line, can you look at "ncdump -h file" for both files? Here is from a boundary file from HYCOM:

    double temp_north(ocean_time, s_rho, xi_rho) ;
        temp_north:_FillValue = -30000. ;
        temp_north:long_name = "potential temperature north boundary condition" ;
        temp_north:units = "Celsius" ;
        temp_north:field = "temp_north, scalar, series" ;

[prasannakanti]

Yes madam. I got your point. When I checked the file using ncdump -h , I got the same _fillvalue but the plots in Ferret looks little bit strange. I am attaching the plots for zeta. When I used level qualifier the plots are correct but without the qualifier plots are confusing.

Please take a look.

[kshedstrom]

What can I say? This is again a ferret issue. Good that you found a work-around.